Preparation of catalysts based on iron(III) porphyrins heterogenized on silica obtained by the Sol-Gel process for hydroxylation and epoxidation reactions

Abstract

Catalisadores sólidos foram preparados pela interação de ferroporfirinas com sílica obtida pelo processo sol-gel. A presença da ferroporfirina na matriz de sílica e a morfologia das partículas obtidas foram estudadas por espectroscopia eletrônica na região do ultravioleta e visível, difratometria de raios X de pó, espectroscopia vibracional na região do infravermelho, microscopia eletrônica de transmissão, ressonância paramagnética eletrônica e análises termogravimétricas. A atividade catalítica dos sólidos obtidos foi investigada frente a oxidação dos substratos (Z)-cicloocteno, cicloexeno e cicloexano por iodosilbenzeno em meio de diclorometano e acetonitrila. Os resultados catalíticos obtidos foram comparáveis àqueles observados quando as ferroporfirinas em solução (catálise homogênea) foram utilizadas.Solid catalysts have been prepared by chemical interaction of iron(III) porphyrins with the surface of the pores of a silica matrix obtained by the sol-gel method. The presence of the complexes in the silica matrix and the morphology of the obtained particles were studied by UV-Vis spectroscopy, powder X-ray diffractometry, infrared spectroscopy, transmission electron microscopy, electron paramagnetic resonance and thermogravimetric analysis. The catalytic activity of the immobilized iron(III) porphyrins in the oxidation of (Z)-cyclooctene, cyclohexene and cyclohexane was evaluated in dichloromethane/acetonitrile 1:1 solvent mixture (v/v) using iodosylbenzene as oxidant. Results were compared with those achieved with the homogeneous counterparts.

Hybrid Materials Based on Silica Matrices Impregnated with Pt-Porphyrin or PtNPs Destined for CO2 Gas Detection or for Wastewaters Color Removal

“…The remarkable interest in porphyrin-functionalized silica hybrid materials is justified by their main characteristics, such as biocompatibility, high chemical resistance and most of all their rich opto-electronical properties [1]. In addition, due to their high specific surface area (usually over 300 m 2 /g) [2], tailored pore shapes and sizes, these hybrid porphyrin-silica materials have tremendous applications in detection (ascorbic acid) [3], the removal of toxic heavy metals [4] and catalysis [5][6][7]. The multiple reuse and easy separation are the major benefits brought by these materials.…”

Investigation of a molybdenum-containing silica catalyst synthesized by the sol–gel process in heterogeneous catalytic esterification reactions using methanol and ethanol

“…The sol-gel process has been widely employed for the immobilization of catalytic species because it allows for the simultaneous control of textural properties and homogeneity [30,31]. The hydrolytic sol-gel route is a two-step process catalyzed in either acidic or basic conditions.…”

Anionic Iron(III) Porphyrin Immobilized on/into Exfoliated Macroporous Layered Double Hydroxides as Catalyst for Oxidation Reactions

“…17,52,67 A typical signal of Fe(III) with rhombic distortion (g = 4.3) arose, which is usual in immobilized FeP systems. 10,68 The estimated D/E ratio was 0.20, which enabled assignment of the observed signals to transitions of the states + −1/2 + and −3/2, with g values of 8.79, 5.77, and 4.28.…”